Strategies to mitigate the challenges in methanol oxidation reaction with contemporary platinum-based electrocatalysts

Abstract

Direct methanol fuel cells are promising energy conversion devices, which traditionally rely on platinum on carbon black (Pt/C) as electrocatalysts to perform electro-oxidation of methanol at the anode. Still, classical Pt/C catalysts suffer from several issues, such as sluggish reaction kinetics, surface poisoning, insufficient durability, and high cost, as they use up to 20 wt% of precious Pt metal as active catalytic sites. To address these issues, several alternative Pt-based electrocatalysts have been suggested as alternatives for methanol oxidation reaction. In this review, we consider selection of constituting materials of the Pt-based electrocatalysts for methanol oxidation, with a focus on their influence on the performance of Pt-active sites, whetheras supports or active co-catalysts. Among different chemical elements from the periodic table, s-block elements primarily modulate the electrode/electrolyte interfaces, while p-, d- and f-block elements tune the electronic structure of Pt and Pt‒Pt bond length through coupling effects, which is beneficial in terms of anti-poisoning electrocatalyst behaviour. We specify the role of those elements in methanol oxidation kinetics and outline contemporary strategies to achieve enhanced performance, durability, and economic viability of the direct methanol fuel cells.